Zheng Haixia, Cheng Chongsheng, He Miao, Zhou Wangji, Li Yixuan, Dai Jinrong, Zhang Ting, Xu Kai-Feng, Zhang Xue, Tian Xinlun, Liu Yaping
McKusick-Zhang Center for Genetic Medicine, State Key Laboratory for Complex Severe and Rare Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, China.
Department of Pulmonary and Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
Mol Genet Genomic Med. 2025 Jan;13(1):e70036. doi: 10.1002/mgg3.70036.
Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disorder characterized by dysfunction of motile cilia. While approximately 50 genes have been identified, around 25% of PCD patients remain genetically unexplained; elucidating the pathogenicity of specific variants remains a challenge.
Whole exome sequencing (WES) and Sanger sequencing were conducted to identify potential pathogenic variants of PCD. Minigene assays were performed to evaluate the pathogenicity of variants. Transmission electron microscopy (TEM) and high-speed video analysis (HSVA) were conducted to analyze the function of cilia in respiratory epithelial cells.
We identified two variants of DNAAF3: c.557G>A, p.G186E in exon 5, and c.1364G>A, p.G455D at the terminal nucleotide of exon 10 in a 16-year-old male patient. Through a minigene assay, we demonstrated that the c.1364G>A variant led to a four-nucleotide skipping. The cilia in epithelial ciliary cells of the proband were almost immotile. The absence of outer dynein arms and inner dynein arms was also observed.
Our study identified two compound heterozygous variants of DNAAF3, a pathogenic gene for PCD, and proved that a novel missense variant c.1364G>A affects splicing. Our findings not only expanded the spectrum of mutations in the DNAAF3 gene but also highlighted the importance of investigating variants of uncertain significance (VUS) for comprehensive genetic diagnoses.
原发性纤毛运动障碍（PCD）是一种罕见的常染色体隐性疾病，其特征为运动性纤毛功能障碍。虽然已鉴定出约50个基因，但约25%的PCD患者在基因方面仍无法解释；阐明特定变异的致病性仍然是一项挑战。
进行全外显子组测序（WES）和桑格测序以鉴定PCD的潜在致病变异。进行小基因分析以评估变异的致病性。进行透射电子显微镜（TEM）和高速视频分析（HSVA）以分析呼吸道上皮细胞中纤毛的功能。
我们在一名16岁男性患者中鉴定出DNAAF3的两个变异：外显子5中的c.557G>A，p.G186E，以及外显子10末端核苷酸处的c.1364G>A，p.G455D。通过小基因分析，我们证明c.1364G>A变异导致四个核苷酸的跳跃。先证者上皮纤毛细胞中的纤毛几乎无运动能力。还观察到外动力蛋白臂和内动力蛋白臂缺失。
我们的研究鉴定出PCD致病基因DNAAF3的两个复合杂合变异，并证明一个新的错义变异c.1364G>A影响剪接。我们的发现不仅扩展了DNAAF3基因的突变谱，还突出了研究意义未明变异（VUS）对于全面基因诊断的重要性。
